Figure 5.

Collectiveness of Xenopus cephalic neural crest cells is maintained by mutual attraction based on autocrine C3a/C3aR signaling. (A) Contact-Inhibition of Locomotion (CIL) polarizes cells toward the cell-free space and therefore acts as a centrifugal force leading to dispersion. (B) Mutual attraction driven by chemoattractant C3a acts as centripetal force promoting gathering of cells. (C) Cell-cell interactions through CIL polarize the distribution and activity of small GTPases within the cells. (D) C3a/C3aR signaling promotes Rac1 activity in cells that have recently left the group. This leads to repolarization and gathering.